Electrical core manufacture



Jan. 9, 1968 A. s. COOPER ELECTRICAL CORE MANUFACTURE ll Sheets-Sheet 1Original Filed April 24 a Na ms. .m

Jan. 1968 A. s. COOPER ELECTRICAL CORE MANUFACTURE ll Sheets-Sheet 2Original Filed April 24 Jan. 9, 1968 1 A. s. COOPER 3,362,066

ELECTRICAL CORE MANUFACTURE Original Filed April 24, 1962 llSheets-Sheet 5 Jan. 9, 1968 A. s. COOPER 3,362,066

ELECTRICAL CORE MANUFACTURE Original Filed A ril 24, 1962 11Sheets-Sheet 4 FIGES.v

Jan. 9, 1968 5 P R 3,362,066

' ELECTRICAL CORE MANUFACTURE Original Filed April 24, 1962 llSheets-Sheet 5 FIGB.

Jan. 9, 1968 A. s. COOPER 3,362,066

ELECTRICAL CORE MANUFACTURE Original Filed April 24, 1962 llSheets-Sheet 6 Jan. 9, 1968 A. s. cooPl-z 3,362,066

. ELECTRICAL CORE MANUFACTURE Original Filed April 24, 1962 llSheets-Sheet 7 Jan. 9, 1968 A. s. COOPER 3,362,066

ELECTRI CAL CORE MANUFACTURE Original Filed April 24, 1962 11Sheets-Sheet 8 339-1 FIGJZ. BE A-Bl 33H 6 0 A-B a l 0 8T N 9*;

ll Sheets-Sheet 9 Original Filed April 24, 1962 Jan. 9, 1968 s. P R3,362,066

ELECTRICAL CORE MANUFACTURE Original Filed April 24, 1962 llSheets-Sheet l0 Jan. 9, 1968 A. s. COOPER 3,362,066

ELECTRICAL CORE MANUFACTURE Original Filed April 24, 1962 llSheets-Sheet 11 United States Patent C) 3,362,066 ELECTRICAL COREMANUFACTURE Alfred S. Cooper, Downsview, Ontario, Canada, assignor,

by mesne assignments, to Central Transformer Corporation, Pine Bluff,Ark., a corporation of Arkansas Original application Apr. 24, 1962, Ser.No. 189,800, now

Patent No. 3,253,439, dated May 31, 1966. Divided and this applicationOct. 1, 1965, Ser. No. 491,909

7 Claims. (Cl. 29605) This application is a division of my applicationSer. No. 189,800, filed Apr. 24, 1962, now United States Patent3,253,439, issued May 31, 1966, for Electrical Core Manufacture.

This invention relates to manufacturing magnetic core members forelectrical induction apparatus, and more particularly to methods formanufacturing wound magnetic core loops.

Among the several objects of the invention may be noted the provision ofimproved methods for manufacturing wound magnetic core loops such as areused in transformers and the like, of the type having a series of stripsegments with flux-transmitting joints and which, while being economicalto manufacture, are low-loss loops and easy to assemble with preformedwindings for forming transformers or the like; the provision of methodsof the class described in which successively longer strip segments areautomatically cut and wrapped to form magnetic core loops, the length ofeach strip-segment being determined by the increase in build orperimeter of the core as the latter is being formed; the provision ofsuch methods which automatically compensate for variations in thethicknesses of the materials with which the core loops are manufactured;the provision of methods in which magnetic core loops of the typedescribed are fabricated from a continuous strip of magnetic material;and the provision of methods for economically manufacturing such coreloops in which flux-transmitting joints are provided in the loop in thecourse of the winding operation, no operations subsequent to the winding operation being required to provide the joints. Other objects andfeatures will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the methods hereinafter described,the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which one of various possibleembodiments of the invention is illustrated,

FIG. 1 is a front elevation of an apparatus (with parts removed) used inthe practice of this invention;

FIGS. 2 and 3 are diagrammatic views illustrating two stages in themanufacture of a magnetic core loop by the methods of the presentinvention;

FIG. 4 is a view in elevation of one type of core loop which may .bemanufactured in accordance with this invention;

FIG. 4A is an enlarged fragmentary view of the core loop of FIG. 4 inelevation;

FIG. 5 is an enlarged end elevation of the apparatus looking from theright-hand end of FIG. 1, with parts removed;

FIG. 6 is an enlarged section taken on line 6-6 of FIG. 1, with partsremoved;

FIG. 7 is a fragmentary section taken on line 7--7 of FIG. 6, with someparts removed and other parts broken away;

FIG. 8 is a plan view of a portion of the apparatus looking from line8-8 of FIG. 5, with parts broken away;

FIG. 9 is a fragmentary rear elevation of a portion of the apparatus,looking from line 9-9 of FIG. 5, with parts broken away and removed;

FIG. 10 is an enlarged fragmentary front elevation of a trip mechanismof the apparatus, with parts broken away;

FIG. 11 is a plan view of FIG. 10, with parts removed;

FIG. 12 is an enlarged rear elevation of a portion of the apparatus,with parts broken away and removed;

FIG. 13 is an enlarged partial section taken on line 13-13 of FIG. 1,with certain parts broken away and removed;

FIG. 14 is an enlarged partial section taken on line 1414 of FIG. 13,with certain parts in a moved position;

FIG. 15 is a view in elevation of FIG. 14, looking from line 15-15 inFIG. 14, with parts removed;

FIG. 16 is a section taken on line 16-46 of FIG. 14, showing certainparts not appearing in FIG. 14 and with other parts broken away andremoved; and

FIG. 17 is a schematic diagram of the control circuit of the apparatus.

Corresponding reference characters indicate corresponding partsthrouhgout the several views of the drawmgs.

The methods of this invention as described herein are particularlyadapted for, although not limited to, the manufacture of magnetic coreloops of the type shown in FIGS. 4 and 4A. These core loops comprise aplurality of individual segments 8-1, 8-2, etc., of magnetic material(such as grain-oriented silicon steel). The segments may, if desired, begrouped into packets such as indicated at P-1 and P-Z. The ends of eachsegment of the core loop shown are butted or nearly butted against eachother to form butt joints J-l, J-2, etc. The joints, such as J-1 andJ-Z, of the segments in each packet also may be offset from one anotherby a predetermined amount, such as five-eights of one inch for example.As will be discussed hereinafter, the number of segments in each packetand the number of packets in each core loop can be varied to produce acore loop of the desired construction and size. While the descriptionand drawings of the apparatus are herein set forth with regard to theproduction of the type of core loop shown in FIG 4, it is to beunderstood that other types of core loops could be made by this method,such as core loops in which the fiux-transmitting joints may be lap aswell as butt type and in which the trailing ends of strip segments havea butt or lap joint relationship with the leading ends of respectivelysucceeding segments, and in which the joints may be radially alignedinstead of respectively offset.

Referring to the drawings, FIG. 1 generally illustrates an apparatus forcarrying out the methods of this invention and FIGS. 2 and 3diagrammatically illustrate the operation of the apparatus. As shown inthese figures, the apparatus generally comprises a core form 1, anendless wrapping belt 3 for rotating the core form, a strip feed rollassembly 5 and a quick-acting cutter or shear 7 mounted on a carriage 9,carriage moving tapes or hands 11, a strip segment hold-down and feedbelt 13, a stop 15, a trip mechanism 17, timing apparatus TA (FIGS. 1and 12-16) for controlling the operation of the shear 7 and tripmechanism 17, and an electrical control system (FIG. 17), a portion ofwhich is mounted in a control box CB (FIG. 1). The core form 1 is shownas being of circular shape for winding circular core loops. Food rollassembly 5 is adapted to feed a continuous strip S of the magnetic metalthrough the shear 7 and toward the stop 15. The

" strip S is withdrawn from a coil (not shown in the drawings due tospace limitations, but which would be 011 to the right of FIGS. 1, 2 and3). The shear 7 is adapted to intermittently cut the strip S intoindividual segments, the leading ends of which segments are kickedupwardly toward the nip of the core form 1 and belt 3 by trip mechanism17 at the proper time to obtain the desired offset between the joints ofthe segments. The carriage 9 and tapes 11 serve as means for moving theshear 7. The holddown and feed belt 13 feeds the segments into the nipof the core form 1 and wrapping belt 3. The core form 1 and belt 3 windthe segments one after another on the core form until a core loop of thedesired number of segments and packets is produced.

The carriage 9 is mounted for linear separation (forward and rearwardmovement) from the core form 1 in respect to the path of travel of thestrip S. Retrograde movement (movement of the carriage to the right asviewed in FIGS. 1, 2 and 3) is effected by bands 11 between each cuttingoperation of the shear 7 so that each segment is successively longerthan the preceding segment. The purpose of cutting each segmentsuccessively longer than the preceding one is to take into account orcompensate for the increase in core loop build, as will be explainedmore fully hereinafter.

To form a core of the type shown in FIG. 4, the carriage 9 is firstmoved to the position shown in FIG. 2, wherein the shear 7 is spacedfrom stop 15 by a distance equal to the circumference or perimeter ofthe core form 1. The feed roll assembly 5 is actuated to feed strip Stoward stop 15. After the leading end of strip S engages stop 15,continued feeding of strip S causes a hump HP (FIG. 2) to be formed inthe trailing portion of strip S between the shear 7 and feed rollassembly 5. When the crest of this hump moves upwardly a predeterminedheight, it actuates a switch SFR which in turn deactuates the feed rollassembly 5. During the dwell period of the strip S the shear 7 is thenautomatically actuated as will be subsequently described to cut thelength of segment S1 from strip S. As soon as strip segment 8-1 is cutfrom strip S, the hump HP of the strip S collapses and flattens therebycausing the leading end of the strip to be moved under the trailing endof the segment S1. As the hump HP collapses, switch SFR becomesdeactuated thus reenergizing the feed roll assembly 5 which resumesfeeding the leading end of strip S toward stop 15. Next, after theoperation of shear 7, trip mechanism 17 is automatically actuated aswill be described hereinafter to kick the leading end of segment S1upwardly toward the nip of the wrapping belt 3 and core form 1 as shownby the dotted line position of the leading end of the strip segment S1in FIG. 2. Feed belt 13 feeds segment S-1 into the nip and the segmentis wound around the core form. Since the trailing end of segment S-1overlies the leading end of the strip S, the feedbelt 13, in addition tofeeding strip segment S1, also exerts a pulling force on the stripthereby aiding the feed roll assembly 5 in moving the leading end of thestrip towards stop 15.

The second strip segment S-2 (FIGS. 4 and 4A) to be cut and wrapped musthave a length equal to the circumference of the first segment 8-1 afterthe latter has been wrapped on core form 1, i.e., the second segment S-2must have a length greater than the length of the first segment by anamount equal to the increase in circumference of the combined core form1 and first segment S1 wrapped therearound over the circumference of thecore form alone. Stating it another Way, the circumference of thesegment 8-1 (after it has been wrapped around core form 1) is greaterthan the circumference of the core form alone by an amount dependent onthe thicknes of strip S. This increase in circumference or perimeter,which is due to the increase in the build, i.e., the increase in thediameter, of the core loop being wound, is equal to 21rt when a circularcore form is employed, where t is the thickness of the strip S. Thesecond segment must therefore have a length which is 21rt longer thanthe first segment. In order to cut the second segment to have such alength the shear 7, which is mounted on carriage 9, must be moved to theright as viewed in FIG. 2 by 21rt. The movement of the shear 7 andcarriage 9 is generally accomplished in the following manner:

As the first segment S--1 is wound on the core form 1,

the length of the portion X (FIG. 2) of the endless belt 3 which engagesthe core form 1 and segment S1 is increased due to the enlargedcircumference of the core form 1 and segment 8-1. The increase in lengthof portion X causes the length of the remaining portion of belt 3 to bedecreased. This decrease causes a sliding roller assembly SR aroundwhich belt 3 is trained to be moved to the right as viewed in FIG. 2 andsuch movement of sliding roller SR causes carriage moving bands 11,which are also trained around sliding roller SR and operativelyconnected to carriage 9, to move the carriage 9 (and the locus of shear7) to the right. Thus the wrapping belt, in addition to its wrapping orcoiling function, forms part of a sensing means for sensing theincreasing build and perimeter of the core loop as the latter is wound;the bands 11 form a part of the means operatively connecting the belt tothe carriage; and the sliding roll assembly SR forms a part of thesensing means and a part ofthe connecting means. While the wrapping belt3 and the rollers around which it is trained might be so arranged and beOlf such size that the movement of carriage 9 would be exactly 21rtbetween each shearing operation, the particular arrangement of belt 3and its rollers as illustrated actually moves carriage 9 to the right bya distance slightly more than 21rt (due to the inherent change in thegeometrical relationship between the core form 1 and the two wrappingbelt rolls adjacent thereto) during the period between successiveshearing operations. Accordingly, as will be described hereinafter, anadjusting mechanism AM (FIG. 2) connecting bands 11 to carriage 9permits the carriage to be pulled to the right by 21rt. Thus, when theshear 7 is automatically operated to cut the second segment 84, suchsegment will be 21rt longer than the first segment S1. The tripmechanism 17 will be automatically actuated to kick the leading end ofthe second segment upwardly at such a time that the desired offsetbetween the joint 1-1 (FIG; 4A) of the first segment and the joint 1-2of the second segment is attained. p

The operation of the apparatus is continued in substantially the samemanner for succeeding segments and the carriage 9 and shear 7 are slowlymoved to the right as viewed in FIGS. 2 and 3 as the core loop isformed. When it is desired to provide additional packets, such as P2,etc., of wrapped segments, the trip mechanism 17 is automaticallycontrolled to kick the leading end of the first sgement of a succeedingpacket upwardly at the proper time necessary to locate the joint of suchsegment in the proper location. After a core loop of the desired size isobtained, the apparatus is stopped in a manner to be subsequentlydescribed to prevent further winding of segments. The core loop is thenremoved from the core form 1 either manually as subsequently described,or by an automatically operated apparatus not shown.

More particularly, the apparatus includes a supporting frame generallydesignated 19 (FIG. 1). A composite horizontal shaft 21 (FIGS. 1 and 13)is rotatably mounted in an elongate bearing 23 (FIG. 13) extendingthrough a plate 25 (FIGS. 1 and 13). Plate 25 is adapted to slide freelyin inclined guides 27, 29 attached to frame 19. The core form 1 isremovably mounted on one end of shaft 21. Endless wrapping belt 3 (FIG.1), which rotates core form 1, is trained around the core form, rolls'31, 33-, 35, 37 and 39 (which are rotatably connected to frame 19) andtensioning or sliding roller SR which is mounted for horizontal slidingmovement in a track 41. Roll 33 (FIG. 1) is driven by a motor M (FIG.12) and a conventional speed changer 42 through an electrically operatedclutch 43, a conventional speed-reducing apparatus 45, a belt 47, and apulley 49 connected to the shaft 51 of roll 33. Thus, rotation of roll33 causes the belt 3 to rotate core form 1. As the strip segments 8-1,S-2, etc. are fed into the nip of the core form 1 and wrapping belt 3,the successive segments will be wrapped around the core form and thepreviously wrapped segments, thus increasin the build of the core loop.The axis of rotation of the core form 1;

i.e., the axis of the core loop being wound, moves upwardly in responseto the increasing radius of the core loop. A U-shaped restraining arm 53(FIGS. 1 and pivotally attached to the shaft 51 of roll 33 and biasedtoward core form 1 has cantilevered springs 54 (FIG. 10) which retainthe leading end of each segment against the core form 1 or previouslywrapped segments as each segment is wound. Sliding roll SR (FIG. 1) isbiased away from the core form 1 by bands 11, thereby keeping tension onbelt 3, but is drawn toward the core form as the core being woundincreases in circumference. The belt 3 may be provided with transversenotches and rolls 31, 33, 35, 37, and SR may be provided with teethadapted to fit within the notches to assure a positive drivingrelationship therebetween.

The strip feed roll assembly 5 (FIGS. 1 and 5) includes upper and lowerfeed rolls 55 and 57, respectively, rotatably mounted in a roll supportassembly 59 attached to carriage 9. Assembly 59 (see FIG. 5) includestwo side channels 61, 63, a plate 65 extending across the upper edges ofchannels 61, 63, a pair of legs 67, 69 extending upwardly from plate 65,and a bar 71 extending across the upper ends of legs 67, 69. Lower roll57 is rotatably journalled in legs 67, 69 and upper roll 55 is rotatablyjournalled in an inverted U-shaped roll carrier 73 which is slidablymounted in legs 67, 69. Upper roll 55 is adapted to frictionally engagethe upper surface of strip S. A bolt 75 extending through bar 71 andengaging the roll carrier 73 prevents upward movement of upper roll 55.

Referring to FIGS. 5 and 12 it will be seen that lower feed roll 57 hasa shaft 77 which extends through the leg 69. A gear 79 is attached tothe end of shaft 77. Gear 79 is driven by an endless chain 81 whichpasses around gear 79, a pair of idler gears 83, 85 located on carriage9, a gear 87 located at one end of the supporting frame 19, and a gear89 (FIG. 12) on the output shaft (not shown) of an electrically operatedclutch and brake as sembly 91. An input shaft 93 of the assembly 91 isprovided with a pulley 95 which is driven from motor driven shaft 51 bya belt 97. It will be seen that the drive arrangement for the lower feedroll 57 is such that roll 57 will be driven even while the carriage 9 ismoving as described hereinafter. Switch SFR, which controls theoperation of feed rolls 55, 57, is mounted on a rod 101 (FIG. 1)extending upwardly from the carriage 9 between the feed roll assembly 5and the shear 7. Switch SFR is actuated by the engagement anddisengagement therewith of hump HP (FIG. 2) as described previously. Theswitch is adapted to control the operation of the clutch and brakeassembly 91 (FIG. 12) which in turn controls the movement of the lowerfeed roll driving chain 81.

Feed roll assembly 5 also includes a lower guide and support plate 103(FIGS. 1 and 5) on which strip S is adapted to be supported and guidedinto the nip of feed rolls 55 and 57. Plate 103 is attached to the legs67, 69 and extends to the right of the legs as viewed in FIG. 1. Theplate 103 is also narrowed and flared downwardly at its outer end asindicated at 105. A pair of arms 107, 109 (FIGS. 1 and 5) is attached tolegs 67, 69. These arms extend to the right of legs 67, 69 as viewed inFIG. 1 and are joined at their outer ends by a cross bar 111 extendingacross and above plate 103. Attached to and extending to the right ofcross bar 111 as viewed in FIG. 1 is an upper guide plate 113 having anarrowed and upwardly flared outer end 115 in vertical alignment withthe flared end 105 of lower plate 103. A weight 117 (FIG. 5) is locatedbelow cross bar 111 and is held against horizontal movement by a handle119 extending upwardly therefrom through a slot 121 (FIG. 5) in crossbar 111. Weight 117 is adapted to frictionally bear upon strip S as thefed rolls 55, 57 pull the strip from the supply to prevent whipping ofthe strip. A pair of side guide rollers 125, 127 (FIG. 5) is mounted ona scissors device 129 pivotally connected to the lower surface of lowerplate 103 as indicated in FIG. 5 at 131. The rollers 125, 127 are 6adapted to engage the sides of the strip S and hold the strip in theproper lateral alignment for reception by the feed rolls. The guiderollers 125, 127 are also adapted to be clamped in different positionsfor guiding strips S having different widths by a clamping screw 132(FIG. 5

The quick-acting shear 7 (FIGS. 1, 5, 6 and 7) which cuts segments fromstrip S includes a housing 133 attached to carriage 9. Mounted onhousing 133 is a horizontal shear bed plate 135 (FIG. 7), and mounted onthe bed plate 135 is a blade holder 137 to which is secured a lowerhorizontal fixed transverse shear blade 139. Extendin g upwardly fromopposite ends of bed plate 135 are vertical guide posts 141, 143 (FIG.6). At 145 (FIGS. 6 and 7) is indicated a composite horizontal shearhead plate. Mounted on the bottom of head plate 145 is a blade holder147 to which is secured a transversely angled shear blade 149. The blade149 is held in an angled position by horizontal bolts 151 and verticalbolts 153. The head plate 145 has vertical cylindrical guide holes 155,157 at its ends through which posts 141, 143, respectively, pass.

A strip hold-down roller 159 (FIGS. 1, 6) is supported by an arm 161connected to head plate 145 and extending to the right as viewed inFIG. 1. The purpose of this roller is to guide the strip so that theconfiguration of each of the humps HP will be such as to actuate switchSFR. A strip hold-down bar 163 (FIGS. 6 and 7) adapted to hold strip Sdown against the lower blade holder 137 as shearing is performed isslidably connected to the head plate 145 by bolts 165, 167 attached tobar 163 and slidably received within holes 169, 171, respectively, inhead plate 145. Springs 173, surround the respective bolts 165, 167 andbias the holddown bar 163 away from head plate 145. A support bed 177(FIGS. 1, 6 and 7) extends between the feed roll assembly 5 and thelower shear blade holder 137 for supporting the strip S therebetween. Apost 178 (FIGS. 6 and 7) extends between shear bed plate 135 and thelower surface of bed 177 for supporting the bed 177.

The driving mechanism for moving the upper shear blade 149 downwardly totransversely cut strip S and upwardly to a retracted position includestwo links 179, 18 1 (FIGS. 5 and 6) rotatably connected to the ends ofhead plate 145. The links 179, 181 are attached at their lower ends toyokes 183, 185, respectively. Yoke 183 has a bearing 187 (FIG. 6) andyoke has a bearing 189, which bearings are eccentrically journalled on ashaft 191 which extends through housing 133. Mounted on shaft 191between the bearings 187, 189 and housing 133 are two cams 193, 195(FIG. 6), the construction and purpose of which will become apparent ashereinafter explained. Mounted on shaft 191 inside of housing 133 aretwo gears 197, 199 (see FIGS. 6 and 7) spaced apart from one another.Gear 197 is adapted to be driven by a rack 201 connected to a piston rod203 of an air cylinder 205 (FIGS. 5, 6 and 7) and gear 199 is adapted tobe driven by a rack 207 connected to a piston rod 209 of an air cylinder211. Air is supplied to both ends of each of the cylinders 205, 211through lines 213, 215 and 217, 219 (FIG. 5) connected to conventionalair valves PAV-L and PAV-R (FIGS. 1 and 17) in such manner that, as seenin FIG. 7, for one shearing operation rack 201 will be driven to theleft when rack 207 is driven to the right. The purpose of this doublerack drive is to counterbalance the shock created by each air cylinderpiston upon completing a stroke. If only one rack were used, the shockcreated by its piston upon completing a stroke might be of suchintensity that the carriage 9 would be bounced or moved in one directionor the other, which uncontrolled carriage movement could adverselyaffect the operation of the apparatus as will become apparent. Thelength of the stroke of the racks is such that the shaft 191 is rotatedslightly less than 360 during one stroke of the racks. As will beunderstood, one revolution of shaft 191 will cause the upper shear blade149 to be moved from a raised position down to cutting position and backto a raised position. At the time of the next shearing operation, therack 207 will be driven to the left and the rack 291 to the right asviewed in FIG. 7.

Two switches LSL and LSR (FIGS. 5, 6 and 17), the purpose of which willbe set forth in the discussion of the control circuit and the operationof the apparatus, are attached to the sides of housing 133 and have arms225, 227, respectively, adapted to engage cams 193 and 195,respectively. The cams 193 and 195 are so constructed that during onecycle of upper shear blade 149, i.e., movement of shear blade 149 downto cutting position and back to a raised position, switch LSL will beactuated just after the shear blade begins its downward movement andswitch LSR will be actuated just before the shear blade reaches itsraised position, i.e., just before the end of a cycle. During the nextshearing cycle the switches are actuated in a reverse sequence, i.e.,switch LSR is actuated just after shear blade 149 begins its downwardmovement and switch LSR is actuated just before blade 149 reaches itsraised position, because the shaft 191 will be driven slightly less than360 in a reverse direction by racks 201, 207.

A switch LSB (FIGS. 5, 6 and 17), the purpose of which will besubsequently described, is connected to the carriage 9 and has aswitch-actuating arm 231 adapted to be actuated by the yoke 185 when theyoke reaches its lowermost position during a shearing cycle, i.e., whenthe shear blade 149 reaches its lowermost or cutting position.

Another switch 233 (FIGS. 1 and 6), the purpose of which is to stop theoperation of the feed rolls as will also be subsequently described, ismounted on an arm 235 (FIGS. 1 and 6) which extends upwardly fromcarriage 9. Switch 233 includes a switch arm 239 adapted to engage anadjustable cam member 241 (FIG. 1) slidably mounted on the supportingframe 19 when the carriage 9 has moved a predetermined distance to theright as viewed in FIG. 1. This distance is that necessary to cut fromstrip S a segment having a length which is equal to the desired outsidecircumference of the core loop after the latter is wound. In otherwords, assuming for example it is desired to form a core loop having acircumference of 40 inches, the cam member 241 is so positioned on frame19 that the switch 233 is actuated after a strip segment of 411 incheshas been cut from strip S. The feed rolls will then be stopped, thuspreventing any further segments being cut from strip S. Therefore, the40-inch strip segment is the outside or last segment of the core loop.

The carriage 9 (FIGS. 1, 5 and 6), which carries the feed roll assembly5 and the shear 7, includes two sets of wheels 243, 245 riding on rails247, 249 (FIGS. 5 and 6) which are secured to frame 19. As statedpreviously, the carriage 9 (and shear '7) is moved 2m to the right asviewed in FIGS. 1, 2 and 3 between each shearing operation.

The carriage moving bands 11 (FIGS. 1, 2, 3, 5, 8 and 9) are provided toaccomplish the above described move ment of carriage 9. These bands arepreferably constituted by a length of flexible steel tape or by bandsthe ends of which are attached as illustrated at 251 to the left end ofthe supporting frame 19 as viewed in FIGS. 1, 2 and 3. The bands 11 aretrained around sliding roll SR on opposite sides of wrapping belt 3,around rolls 253, 255 and 257 (rotatably attached to frame 19),operatively connected to the carriage 9 as will be subsequentlydescribed, and then trained around an air cylinder biased roll 259connected to the piston rod of an air cylinder AC. The other ends of thebands 11 are attached at 2 51 to frame 19. With this arrangement it willbe seen that a certain increase in the length of the portion X of belt 3causes the remaining portion of the belt to be decreased a like amount.Accordingly, the sliding roll SR is moved to the right in FIGS. 1, 2 and3 one-half the amount of decrease in the remaining portion of belt 3. Acertain amount of movement of sliding roll SR to the right as viewed inFIG. 1 will cause a reference point P (to the right of carriage 9 inFIGS. 1, 2 and 3) on bands 11 to move to the right exactly twice as muchas roll SR due to bands 11 being trained around roll SR and beingconnected to frame 19 at 251. Thus, the point P moves to the rightexactly the same amount as the increase in the length of portion X ofbelt 3. It will be noted that this relationship in movement betweenpoint P and the increase in portion X is maintained regardless of therelative diameters of the portions of roll SR around which the belt 3and bands 11 are trained. The air cylinder biased roll 259 (which isbiased to the left in FIGS. 1, 2 and 3 by the air cylinder AC) will bepulled to the right the same amount as sliding roll SR moves to theright.

As mentioned previously, the specific arrangement of the endlesswrapping belt 3 and the rolls 31, 33, 35, 37, 39 and SR as illustratedherein is such that as one segment is being wound on the core form 1 thesliding roll SR is pulled to the right as viewed in FIG. 1 by an amountslightly different than is necessary to obtain precisely a Z-rrtmovement of carriage 9 and shear 7. Accordingly, if the bands 11 wereconnected directly, i.e., fixed, to carriage 9, the latter and shear 7would be moved slightly too far to the right as viewed in FIG. 1 to cuta segment having an increase in length of only 2111 over the length ofthe previously cut segment. One convenient way to correct or compensatefor this is to connect bands 11 to carriage 9 in such a manner that thecarriage does not move as far to the right (FIG. 1) as point P, duringeach cycle of operation. This is accomplished by adjusting mechanism AMwhich includes a cross clamp 263 (FIGS. 1 and 8) extending between bands11 beneath carriage 9. A rack 26'5 (FIGS. 5, 8 and 9) is secured inclamp 263 and extends toward roll 257 (FIG. 1). This rack is slidablyreceived in a U-shaped guide 267 (FIGS. 5 and 8) rigidly attached tocarriage 9. A spring 269 (FIGS. 1, 5 and 9) pulls clamp 263 toward theguide 267.

Rack 265 is in mesh with a gear 271 (FIGS. 5 and 8) having a shaft 273rotatably journalled in one leg of guide 267 and a bearing 275 mountedon the right edge of carriage 9 as viewed in FIG. 5. Rigidly attached onthe outer end of shaft 273 is an arm 277 (FIGS. 5, 8 and 9) having aroller 279 mounted on the outer end thereof. The roller 279 engages anadjustable elongate cam 281 (FIGS. 5, 8 and 9) mounted on supportingframe 19. As the point P on bands 11 is pulled to the left as viewed inFIG. 9 (to the right as viewed in FIG. 1), the rack 265 will be pulledto the left the same amount. If the elongate cam 281 were exactlyhorizontal (rather than lnclmed downwardly) the arm 277 could not rotateclockwise as yiewed in FIG. 9. Thus the rack 265, gear 271 and carriage9 would be moved the same amount as point P on bands '11. However, sincecam 281 is inclined downwardly to the left as viewed in FIG. 9, the arm277 is permitted to rotate a slight amount in a clockwise directron asthe carriage 9 moves away from core form 1. Thus when the point P onbands 11 is moved a certain distance to the left as viewed in FIG. 9,the gear 271, while being moved to the left most of this distance, willcrawl a small amount to the right relative to the rack 265 as a resultof the arm moving in a clockwise (as viewed in FIG. 9) direction a smallamount. Therefore, the gear 271 and consequently the carriage 9 will notmove away from the core form 1 as much as the point P on bands 11. Byadjusting the inclination of elongate cam 281, the carriage may be madeto move 2m to the right as viewed in FIG. 1, although point P on hands11 may move more than 2n! during each period between successiveactuations of the cutter. It will be recalled that the carriage movementis dependent on the thickness t 9 of strip S. Thus, variations in thethickness 1 of strip S are automatically compensated for by thisapparatus.

The strip segment hold-down and feed belt 13 (FIG. 1) frictionallyengages and holds down the strip S while the latter is fed toward stop15 on a double-rail table 282 (FIGS. 1, 10 and 11) connected to carriage9 between trip mechanism 17 and shear 7. Belt 13, which also functionsto feed successive strip segments into the nip of the core form 1 andwrapping belt 3, is trained around rollers 283, 285, 287 and 289(FIG. 1) which are mounted on supporting frame 19, and rollers 291 and293 mounted on the arm 235 which extends upwardly from carriage 9. Thebelt is driven by roller 285 which is driven through a belt and gearconnection 295 (FIG. 12) by motor-driven shaft 51. Belt 13 merely slidesover the strip segment positioned therebeneath until the trip mechanism17 kicks the leading end of the segment upwardly, at which time the beltforces the segment into the nip of the core form 1 and wrapping belt 3.

The stop 15 and trip mechanism 17, which stop and kick, respectively,the leading end of each of the strip segments upwardly toward the nip ofthe core form 1 and wrapping belt 3 at the proper time to obtain thedesired offset between the joints of adjacent segments, are shown on anenlarged scale in FIGS. 10 and 11. The stop 15 is mounted on one leg(the left-hand leg as viewed in FIG. 10) of a composite U-shaped base297 and extends up- Wardly across the path of the strip S. The strip Swill be fed toward the stop 15 by the feed rolls 55 and 57 (FIG. 1)until the forward end of the strip abuts stop 15. As the feed rollscontinue to feed strip S, hump HP will be formed by the strip betweenthe feed roll assembly 5 and the shear 7 (see FIG. 2). The formation ofthe hump HP is aided by the hold-down roller 159 (FIGS. 1 and 6). Thishump will actuate switch SFR which causes clutch and brake assembly 91(FIG. 12) to stop the feed rolls 55, 57. As the leading end of strip Sabuts stop 15 it also actuates a switch MS by engaging and moving to theleft (as viewed in FIG. 10) a switch arm 303. The purpose of this switchMS is to indicate that the steel strip S has reached the stop asdescribed hereinafter.

Pivoted on the upper end of the left-hand leg of base 297 as viewed inFIG. 10 is a finger support 305 having holding fingers 307, 309 thereon.The support 305 and fingers 307, 309 are movable between a holdingposition (solid-line position in FIG. 10), wherein the fingers arepositioned over the leading end of a strip S and aid the hold-down belt13 in holding the strip down on table 282 while shearing takes place,and a retracted position (dotted-line position in FIG. 10), wherein thefingers 307, 309 are out of the path of the strip S. The pivotalmovement is accomplished in a manner to be described subsequently.

A first pair of rollers 311 is attached to the right-hand leg of base297 by a roller mount 313. Rollers 311 are adapted to engage the lowersurface of strip S to press the latter against hold-down belt 13. Asecond pair of rollers 314 (FIG. 11), mounted on the right-hand leg ofbase 297, is adapted to engage the side edges of strip S to preventlateral movement thereof.

Pivotally attached to the upper end of the right-hand leg of base 237 asviewed in FIG. 10 is a roller support 315 in which is mounted a pinchingroller 317. A tripping finger 319 extends upwardly from an arm 321 ofroller support 315 to a position just below the leading end of strip Swhen the latter abuts stop 15. The roller support 315 is adapted to bemoved from a retracted position solid-line position in FIG. 10) whereinthe tripping finger 319 and roller 317 are below the path of strip S toa tripping position wherein the tripping finger kicks the leading end ofa segment of strip S upwardly and roller 317 pinches the strip segmentagainst belt 13 to feed the segment under U-shaped restraining arm 53into the nip of core form 1 and the wrapping belt 3.

The holding fingers 307, 309, the tripping finger 319,

10 and the pinching roller 317 are adapted to be moved from theirsolid-line positions in FIG. 10 to their dotted-line positions by an airoperated trip cylinder 323 having a piston 325.

Piston 325 is biased downwardly by a spring (not shown) and is adaptedto be moved upwardly when air is supplied to the lower end of cylinder323. As will be described hereinafter, after the shear 7 has cut asegment from strip S, air is supplied to cylinder 323 from an air source(not shown) upon energization of a solenoid valve AVT (shown in FIG. 17only). The upper end of piston 3.25 is attached by a pin and slotconnection 327 to arm 321 of roller support 315. A link 329 connectsholding finger support 305 to a projection 331 extending downwardly fromarm 321 so that the holding finger support 305 and roller support 315will pivot in opposite directions at the same time. It will thus be seenthat upward movement of piston 325 causes the roller support 315 and theholding finger support 305 to pivot clockwise and counterclockwise,respectively, as viewed in FIG. 10, thereby causing the holding fingers307, 309, the tripping finger 319, and the pinching roller 317 tobemoved to their dotted-line positions. This causes the leading end of asegment of strip S to be kicked upwardly toward and fed into the nip ofthe core form 1 and wrapping belt 3.

The timing apparatus TA for controlling the operation of the shear 7 andtrip mechanism 17 is shown in FIGS. l216. The timing apparatus is soconstructed that the shear is operated to cut each segment from strip Sand the tripping mechanism is operated to kick each segment upwardly atthe proper time in order to wind a core loop raving the abutting ends ofeach segment offset from the abutting ends of the preceding segment bythe desired distance. This apparatus essentially includes a commutatordisc or plate 337 (FIG. 12) having a plurality of curved orarcuate-shaped electrically conductive segments 339-1 through 339-20(FIGS. 12 and 17) fixed on the outer face thereof, and a brush carryingplate 341 having a shear operating brush BS, a trip mechanism operatingbrush BT and an end-of-cycle brush BE connected thereto (FIGS. 12, l3,l4 and 16), the brush plate being adapted to move spirally outwardly asthe core form rotates and the core loop being wrapped increases in outside diameter. As will hereinafter be made apparent the brushes BS, BTand BE carried by brush plate 341 must rotate at the same rate as thecore form 1 and also move outwardly in a radial direction from thecenter of the commutator plate 337 the same amount and at exactly thesame rate as the radius of the core loop being wound increases. Thus, asthe core loop being wound is built from a core loop having a radius of 2inches, for exam ple, to a core loop having a radius of 8 inches, forexample, the brushes BS, BT and BE in addition to rotating at the samespeed as the core form 1 must move outwardly in a radial direction fromthe center of the commutator plate 337 from 2 inches to 8 inches.

The brush carrying plate 341 and brushes BS, BT and BE are mounted forthe above type of movement by the following apparatus:

As will be seen in FIGS. 1 and 13, an arm 343 is connected to slidingplate 25 on the rear side of the apparatus. commutator plate 337 isconnected to the outer end of arm 343 by a bracket 345 (FIG. 13). Thus,as sliding plate 25 and the axis of rotation of the core form 1 moveupwardly in response to the increase in build up of the core loop beingwound, the arm 343, bracket 345 and commutator plate 337 are also movedupwardly at the same rate as the center of the core form 1.

Mounted within the outer end of .arm 343 is a bearing 347 (see FIG. 14)in the center of which another bearing 349 is rotatably mounted. Theinner race of bearing 349 is secured to a tubular shaft 351 whichextends outwardly (to the left as viewed in FIG. 14) through a bearing353 in bracket 345 and a hole 355 in commutator plate 337. An arm 357 isattached to tubular shaft 351 to the left of the commutator plate asview in FIG. 1-4 and carries a brush guide track 359 (see FIG. 16)thereon. The purpose of track 359 will be later explained. Mounted ontubular shaft 351 adjacent arm 357 is a rack support 361 (FIGS. 14 and16) in which two racks 363, 365 are slidably mounted. As will bedescribed hereinafter, the lengthwise movement of racks 363, 365 isunder control of a pair of gears 367 (FIGS. 13 and 14). The racks 363,365 are tied together at one end thereof by brush carrying plate 341(see FIG. 16). The brushes BS, BT and BE (see FIG. 14), brush plate 341,racks 363, 365, gears 367, rack support 361, arm 357, guide track 359and tubclar shaft 351 will therefore rotate together. The shaft 51, andtherefore brushes BS, BT and BE, are adapted to be rotated at the samespeed as core form 1 by a belt 369 (FIGS. 13, 14 and trained around apulley 371 on shaft 351 and around a pulley 362 (FIG. 13) of the samediameter as pulley 371 on the core form shaft 21.

Referring now to FIG. 14, it will be seen that another rack support 374is mounted between the inner race of bearing 347 and the outer race ofbearing 349. Two racks 3'75, 377 (FIGS. 14 and 15) are slidably mountedin support 374 and are tied together at their lower ends by a clamp 379pivotally connected to the supporting frame 19. A shaft 381(FIG. 15) isrotatably mounted in ears 383, 385 extending away from rack support 374.The shaft 381 is provided with three gears 387, 389 and 391. Gear 387extends through an opening (not shown) in rack support 374 and mesheswith rack 375. Gear 389 extends through another opening (not shown) inrack support 374 and meshes with rack 377. Gear 391 extends through anopening 392 (FIG. 14) in a tubular member 393 secured at one end withinthe rack support 374. With this arrangement of parts, upward movement ofsliding plate (FIG. 1) as a result of the increase in build of the coreloop being wound will cause the arm 343, bearing 347, rack support 374,ears 383, 385, shaft 381, gears 337, 389, 391 and tubular member 393 tomove upwardly at the same rate as plate 25. Since racks 375, 371 areheld against upward movement by the pivotal clamp' 379, the racks willcause gears 387, 389, and consequently shaft 381 and gear 391, to rotatein a counterclockwise direction as viewed in FIG. 14.

Gear 391 is in mesh with a rack 395 slidably mounted within tubularmember 393. As the gear 391 is rotated counterclockwise as viewed inFIG. 14, rack 395 will move to the right. A thrust bearing 397 having arotatable center portion 399 is attached to the left end of rack 395(FIG. 14). The rotatable center portion 399 is keyed as indicated at4111 to a rack holder 4113 slidably connected to the interior of tubularshaft 351. A rack 435 is held within holder 403. Thus, upon movement ofrack 395 to the right as viewed in FIG. 14, the rack 405 will be pulledto the right by rack holder 403 and thrust hearing 397, even though rack405 and rack holder 403 are rotating with tubular shaft 351.

Rack 4115 drives a gear 407 (similar to gear 391 in FIG. 14) extendingthrough an opening 409 (FIGS. 14 and 16) in tubular shaft 351. Gear 407is attached to a shaft 411 mounted in ears 413, 415 (see FIG. 16) onrack support 361. Also mounted on shaft 411 is the pair of gears 367(only one of which is shown in FIG. 14 but which are similar to gears387, 339) which extend through openings 419, 421 (FIG. 16) in racksupport 361 into meshing engagement with racks 363, 365. It willtherefore be seen in FIG. 14 that movement of rack 4115 to the right asviewed therein will cause the brushes BS, BT and BE to move downwardlyas viewed in FIG. 14, i.e., outwardly from the center of the commutatorplate 337 in a radial direction.

In order to insure that each of the brushes BS, BT and BE is movedradially outwardly exactly the same amount, the brush BS is connected tobrush carrying plate 341 by a bell crank 423 (FIG. 16). Brush BS ismounted on the outer end of one arm of hell crank 423 and a follower 425is mounted on the outer end of the other arm of the bell crank. Brush BEis connected to plate 341 by a bell crank 427 in the same manner asbrush BS, i.e., brush BE is on the outer end of one arm of hell crank427 and a follower 429 is on the outer end of the other arm of the bellcrank. Followers 425 and 429 respectively ride in grooves 431 and 433 inbrush guide track 359. The grooves are so arranged that while the brushcarrying plate 341 is moving downwardly as viewed in FIG. 16, thebrushes BS and BE are maintained at exactly the same distance from thecenter of tubular shaft 351 as the brush BT, which is fixed to brushcarrying plate 341.

With the above described arrangement of parts it will be seen that asthe core loop being wound increases in diameter, the brushes BS, BT andBE will rotate around the center of the commutator plate 337 at the samespeed that the core loop is rotating, and also move outwardly of thecenter of the commutator plate 337 in a radial direction at the samerate that the radius of the core loop increases. The complete timingassembly TA moves upwardly at the same rate as the axis of rotation ofthe core form 1. Thus, the movements of the various parts of the timingapparatus TA are proportional to the movements of certain elements ofthe core form 1 and the core loop being wound.

Referring now to the commutator plate 337 (FIG. 12) construction per se,it will be recalled that a plurality of curved electrically conductivesegments 339-1 through 339-20 are provided on the outer surface thereof.Any number of such segments may be provided and in the embodimentdiscussed hereinafter only segments 339-1 through 339-18 are connectedinto the control circuit. Each of these segments is electricallyconnected by a ditferent conductor to a respective contact of a steppingswitch W1 (shown in FIG. 17 only) which constitutes one portion or deckof a three-deck assembly that also includes stepping switches W2 and W3.Thus, conductive segment 339-1 is connected to contact number 1 of W1,segment 339-2 to contact number 2-, and so on. Switch W1 has a movablearm or rotor 436' which selectively connects commutator segments 339-1through 3 39-18 to terminal 437 in the control circuit of FIG. 17. Arm436 is stepped or advanced from one contact of switch W1 to the adjacentcontact by a coil MM within a stepping relay Brushes BS, BT and BE areconnected in the control circuit by wires 439, 441i; and 441, and aconventional slip ring assembly 443 (FIGS. 12, 13, 14 and 17). As willhereinafter become apparent, when brush BS contacts conductive segment339-7 (assuming, for example, that this is the conductive segmentinitially connected to point 437 by switch W1) the shear 7 will beoperated to cut the first strip segment 8-1 from strip S; when brush BTcontacts conductive segment 339-7 the trip mechanism 17 kicks theleading end of the first strip segment upwardly toward the nip of coreform 1 and wrapping belt 3; and when brush BE contacts conductivesegment 339-7 various relays in the control circuit are actuated alongwith coil MM which steps arm 436 connecting a second conductive segment339-8 into the control circuit at point 437. When brushes BS and BT thencontact conductive segment 339-3 the second strip segment is cut andkicked upwardly, respectively; and when brush BE contacts conductivesegment 339-3 coil MM is again actuated, stepping arm 43 6 to connectconductive segment 339-9 to point 437. The above sequences are repeatedfor succeeding conductive segments for the number of times necessary toobtain a core loop packet having the desired number of strip segmentstherein. The control circuit then causes arm 433 to connect theoriginally connected conductive segment (such as 339-7) to point 437 andthe packet cycle is repeated. For example, if it is desired to make acore loo-p having two concentric packets with six segments in eachpacket as shown in FIG. 4, switch W1 will progressively connectconductive segments 339-7 through 339 12 to point 437. After sixsegments have been wound on the core form, the control circuit will beeffective to cause ar-m 436 to again connect conductive segment 339-7into the control to the circuit of point 437 to initiate the building ofthe second packet P-2. After the last segment of the second packet P-2is cut from strip S, the switch 23-3 (FIG. 1) is actuated by theengagement of its arm 23-9 with cam 241 and deactuates the clutch andbrake assembly 91 (FIG. 12), thereby preventing further feeding of stripS by stopping feed rolls 55 and 57. Clutch 43 (FIG. 12) is disengaged bya manually operated switch (not shown) to stop the rotation of the coreform and the core loop is removed in a manner to be subsequentlydescribed.

The arrangement of conductive segments 339-1 through 339-118 is suchthat the distance traveled by any one of the brushes BS, BT or BE aseach moves spirally around the commutator plate 337 in acounterclockwise direction as view in FIG. 12 between first contactingone conductive segment and first contacting a succeeding conductivesegment is equal to the distance that the brushes would travel duringone complete revolution minus the desired ofiset between the abuttingends of the one strip segment and the abutting ends of the succeedingstrip segment of the core loop shown in FIG. 4. For example, if anoffset of five-eighths of one inch were desired between abutting ends ofone strip segment and the abutting ends of the succeeding strip segment,the distance that the brushes would travel between first contacting oneconductive segment, for example segment 339-1, and first contacting asucceeding conductive segment, such as segment 339-2, would be thedistance that the brushes would travel during one complete revolutionminus five-eighths of one inch. This five-eighths of one inch distanceis represented by dotted line A-B in FIG. 12. This five-eighths of oneinch separation remains constant even though the brushes move radiallyoutwardly from the center of the commutator plate, i.e., the line A-Brepresents the distance that the brushes do not have to travel tocontact segment 335 -2 when the brushes are relatively close to thecenter of the commutator plate, and the line A-B1 represents thedistance that the brushes do not have to travel to contact segment 339-2when the brushes are farther away from the center of the commutatorplate, such as when the second packet of strip segments is to beinitiated. Lines A-B and A-B l are equal in length. This samerelationship exists between each segment and the succeeding segmentthroughout the lengths of the segments. It will be understood that bychanging the shape and size of the conductive segments 339-1 through339- other types and configurations of core loops can be produced bythis apparatus.

The control circuit illustrated schematically in FIG. 17 will now beconsidered. In FIG. 17 clockwise rotation of the brushes BS, BT and BEcorresponds to counterclockwise rotation as viewed in FIG. 12. Inaddition to stepping switches W1, W2 and W3, commutator segments 339-1to 339-18, brushes BS, BT and BE and the associated slip ring assembly443, the circuit of FIG. 17 includes a plurality of relays E, H, R, SC,T and U, the switches MS, LSB, LSL and LSR, the air solenoid valve AVT,and the pair of solenoid pilot valves PAV-R and PAV-L. Each relayincludes one or more sets of contacts which are shown bearing likereference designations, Thus, relay E includes contacts E1, E2 and E3;relay H includes contacts H1, H2 and H3; and so on. A pair of conductorsL1 and L2 connected to a source of AC. power (not shown) is provided.Line L2 is grounded. A conventional halfwave rectifier 445 having aninput circuit connected across line L1 and L2 is also provided. The DC.output of this rectifier is applied across a conductor L3 and groundedline L2.

As illustrated in FIG. 10 and explained above, switch MS is closed asthe leading end of a strip S of magnetic material abuts stop 15.Thereafter, assuming for example that the stepping switch W1 connectsconductive segment 339-7 to point 437, and further assuming that thecontacts of switches LSL and LSR are initially positioned as shown (themovable contact of LSL engaging its terminals 1, 4 and the movablecontact of LSR engaging its terminals 2, 3) when brush BS contactsconductive segment 339-7, a circuit is completed energizing solenoidpilot valve PAV-R. This circuit may be traced from conductor L1, throughsolenoid PAV-R, terminals 2, 3 of switch LSR, normally closed contacts5C3, switch MS, slip ring assembly 443, brush BS which contacts segment339-7, stepping switch W1, point 437, and the normally closed contactsH1 to line L2. The energizing of PAV-R causes air to enter air cylinders205 and 211 of the driving mechanism thereby operating shear 7. As thisshear begins its downward stroke, cam (FIG. 6) rotates causing themovable contact or arm of switch LSR to be moved from terminals 2, 3into engagement With terminals 1, 4. A circuit is thereby completedenergizing relay SC. This circuit may be traced from line L1 throughnormally closed contacts E2, relay coil SC, terminals 1, 4 of switchLSR, terminals 1, 4 of switch LSL, to conductor L2. Normally openedcontacts SCI close forming a holding circuit for relay SC; normallyclosed contacts SC3 open, preventing the shear from being reenergizeduntil relay SC has been deenergized; and normally opened contacts SC2close. When the shear nears the bottom of its stroke, switch LSB (FIG.6) closes, energizing relay coil R. This closes normally opened contactsR1, sealing in relay R. Contacts R2 also close. As the shear '7 is aboutto complete its upward stroke, cam 193 (FIGS. 5 and 6) causes themovable contact of switch LSL to engage its contacts 2, 3. As brush BTcontacts segment 339-7, which is grounded through contacts H1, a circuitis made energizing both the air valve solenoid AVT and relay T. Thiscircuit may be traced from line L1 through both air valve solenoid AVTand the coil of relay T, contacts R2, SC2, which are now closed, andcontacts U1, which are normally closed, the slip ring assembly 443,brush BT which is now in engagement with conductive segment 339-7, arm436 of switch W1, and contacts H1 to line L2. The energizing of solenoidAVT supplies air to the trip operating cylinder 323 (FIG. 10) causingthe leading end of the strip segment 8-1 to be kicked upwardly and fedby feed belt 13 (FIGS. 1, 2, and 3) into the nip of core form 1 andwrapping belt 3. Upon the energizing of relay T contacts T1 and T2close, sealing in relay T through normally closed contacts E1 andcontacts R2 and SC2 which are now closed. Contacts T3 also closed. Theclosing of contacts T1 energizes coil MM of stepping relay 438. Thisadvances a plunger (not shown) which, when coil MM is subsequentlydeenergized, will cause the movable arms of switches W1, W2 and W3 toadvance one position. The closing of contacts T3 places the coil ofrelay U across lines L2 and L3, energizing this relay and therebyopening contacts U1 and closing contacts U2. Thereafter when brush BEcontacts the segment 333-7 of the commutator 339, a circuit is madethrough now closed contacts U2, energizing the coil of relay E andopening contacts E1. This deenergizes both relay T and the solenoid AVT.Contacts E2 are reopened, deenergizing relay SC, and contacts E3 areopened, deenergizing relay R. Contacts T1 also open deenergizing coil MMof the stepping relay, causing arm 436 of stepping switch W1 to advanceone position to connect conductive segment 339-8 to point 437. Themovable arms of switches W2 and W3 are concurrently advanced oneposition to their respective contacts number 8. At this point all of therelays and solenoid valves have been deenergized and the control circuitis ready to begin another cycle of operation.

The brush assembly continues to rotate (clockwise in FIG. 17,counterclockwise as viewed in FIG. 12). The leading edge of a secondstrip of magnetic material abuts 15 stop 15, closing switch MS. Sincecontacts 1, 4 of switch LSR and contacts 2, 3 of switch LSL are closedat the beginning of this sequence, solenoid pilot valve PAVL (instead ofPAV-R as before) is energized as brush BS contacts segment 339-8. Exceptfor this, the sequence of operation during this second cycle is the sameas that described above. At the end of this second cycle, the movablecontacts of LSL and LSR are again positioned as shown in PEG. 17 andconductive segment 3399 is connected to point 437 by switch W1. Duringthe next succeeding cycle solenoid pilot valve PAV-R is energized by thecontrol circuit. This operation continues with solenoid pilot valvesPAVR and PAV-L being alternately and successively energized until. adesired number of segments of magnetic material have been wound on thecore,

forming one packet.

A selector switch 147 (FIGS. 1 and 17) is provided to facilitateautomatic control of the number of such segments, i.e., the number ofsegments per packet. This switch has a portion A (FIG. 17) constitutedby a rotor or movable contact 449* associated with a plurality ofterminals 1.143, and a portion B constituted by a rotor or a movablecontact 451 associated with a plurality of terminals 18. Terminals 18 ofswitch 447 are connected respectively to terminals L8 of deck W3, andterminals 11-18 of switch 447 are connected respectively to terminals114.8 of deck W2. The stepped arms or rotors of decks W2 and W3 areganged with arm 436 of deck W1, and the terminals or contacts of W2 andW3 correspond to the terminals or contacts of W1. That is, when arm 436of W1 is in engagement with its terminal number 1, the arms of W2 and W3are each in engagement with their respective number 1 terminals.Contacts 9-18 of W3 are connected to ground. Rotors 449 and 151 aremovable on the same shaft 453 which may be manually positioned inaccordance with the number of segments which are to constitute onepacket. Both of these rotors are connected to ground.

Rotor 44% has a finger or brush 155 which selectively engages one of itscontacts. The position of this finger determines which of terminals 114%of stepping switch W2 is connected to ground. Rotor 451 has a cutout orindent 457 selectively positioned with respect to contacts 1-8. Rotor451 connects all of terminals 1-8 of stepping switch W3 to ground exceptthat terminal which corresponds to the contact opposite indent 457. Theposition of indent 4-57 determines the starting or home position andnumber of the first segment of each packet. Thus, when indent 457 isopposite contact number 7, for example, the first segment of each packetwill be wound when brush BS contacts conductive segment 3394. Theposition of brush 455, on the other hand, determines the stoppingposition or number of the last segment of each packet. Thus, it brush 455 is in engagement with contact 13, segments of magnetic material willbe wound on the core for each contact 7, 3, of stepping switches W1, W2and W3 until the arms of these stepping switches are advanced to theirrespective terminals number 13. When this terminal 13 is engaged, thecontrol circuit causes stepping relay 438 to step or advance the arms ofW1, W2 and W3 from contact to contact until they are again in engagementwith their respective terminals number 7. At this point the arms come torest and a segment of strip S is cut and wound on the core under thecontrol of conductive segment 339-7, thus beginning a new packet.Thereafter strip segments are wound for each of segments 339%), 339-9,339-12. When the arms of stepping switches W1, W2 and W3 again contactterminals number 13, they are again rotated or advanced from terminal toterminal until they again come into engagement with terminal number 7 tobegin the winding of a third packet. This sequence continues until acore of desired dimensions is formed.

Selector switch 447 permits any number of segments per packet to beselected. If this switch is positioned as shown in FIG. 17 there will besix segments per packet, one each for positions '7, 8, 9, 1t), 11 and12. Seven segments per packet would be wound it rotors 449 and 451 wererotated one position clockwise from that shown in FIG. 17, and fivesegments per packet would be wound upon rotation of these rotors onepoistion counterclockwise from that shown in FIG. 17.

Selector switch 4&7 functions to control the number of. segments perpacket in the following manner. Assuming the switch to be set as shown,and further assuming that the segment or strip of core materialcorresponding to position number 12 is being wound on the packet, at theend of this winding sequence relay 43? steps each of the arms of W1, W2and W3 into engagement with its respective contact number 13. As the armof W2 contacts terminal number 13, a circuit is completed whichenergizes relay H. This circuit may be traced from line L3, through thecoil of relay H, the arm of W2 to contact number 13, and through rotor449 to ground. Normally opened contacts H2 and H3 close and normallyclosed contacts H1 open. The opening of contacts H1 disconnects point437 from line L2, thus preventing the operation of that portion of thecontrol circuit shown above line L2 in FIG. 17. The closing of contactsH2 completes a holding circuit for relay H from line L3 through relay H,contacts H2, and stepping switch W3 to ground. The closing of contactsH3 completes a circuit from the positive terminal of a rectifier 159included within the stepping relay 433, through coil MM, an interruptingcontact 461, contacts 113, and the arm of switch W3 to ground.Interrupting contact 461 is controlled by coil MM and is opened whenthis coil is energized and closed when this coil is deenergized. Theenergizing of coil MM advances its plunger (not shown) and open-scontact 461. This deenergizes coil MM stepping the three arms ofstepping switches W1, W2 and W3 to their contacts number 14 and closingcontact 461. Coil MM is again energized, opens contact 461, isdeenergized, closes contact 461, and again advances the arms of switchesW1, W2 and W3, this time to position number 15. The arms of W1, W2 andW3, are advanced from position number 15 to 16, from 16 to 17, from 17to 1 8, from 18 to 1, etc., until the arm of W3 is moved into engagementwith contact number 7, the ungrounded contact. At this point the circuitfrom the positive terminal of rectifier 459 to ground is interrupted andthe closing of interrupting contact 461 no longer energizes coil MM. Thecircuit from rectifier 445 through relays H and contacts H2 to ground isalso interrupted, deenergizing relay H, and causing contacts H2 and H3to open and contacts H1 to close. Point 437' is thus connected to lineL2 through contacts H1, thereby transferring control of the steppingrelay coil MM to the portion of the control circuit shown above line L2.This permits the winding of a segment of strip S for each position 7, 8,9, 1t 11 and 12 of stepping switch W1. As the arm of W2 is again steppedinto engagement with contact number 13, relay H. is again energized, andthe cycle is repeated. This continues until a core loop of predeterminedsize is wound, i.e., until a stripsegment having a length equal to thedesired outer circumference of the core loop is cut by shear 7, at whichtime switch 233 (FIG. 1) is actuated to stop the operation of feed rollassembly 5. Since the strip S is no longer being fed into the apparatus,no further strip segments will be cut and wound.

is stated previously, the clutch 43 is then disengaged by a manuallyoperated switch (not shown) to stop the rotation of the core form 1,i.e., the drive to the wrapping belt 3 is interrupted. The operator thenapplies adhesive coated tape, for example, over the joint formed by theabutting ends of the last segment (the outermost segment) of the coreloop to prevent such segment and all of the remaining inner segmentsfrom springing outwardly after the core loop is removed from the coreform 1.

In the embodiment shown in FIG. 1, the core loop is removed in thefollowing manner:

The air cylinder AC is actuated by a conventional control (not shown) tomove the roll 259 to the right as viewed in FIG. 3. This relieves thebias exerted on bands 11 by the roll 259. The operator then pushes onthe Wrapping belt 3 between rollers 37 and 39 toward the core form 1.Pushing on belt 3 in this manner causes the sliding roll SR andconsequently the carriage 9 to be moved further to the right as viewedin FIG. 3, but it also produces slack in the wrapping belt 3. Theoperator then lifts the core loop, while it is still on the core form 1,upwardly away from the rollers 31 and 33 and pulls the core loop off ofthe core form. In order to facilitate the lifting of the core loop andcore form away from rollers 31, 33, the sliding plate 25 (FIG. 1) may becounterbalanced by a conventional counterbalancing mechanism (notshown). It will be understood that any suitable appraratus could beprovided which would automatically raise the core loop and core form 1and move them outwardly of the wrapping belt 3 to further facilitate theremoval of the core loop.

If the round form of the core loop is satisfactory, the next step is toanneal the core. If a core shape other than round is desired, the roundcore may be formed to the desired shape (for example, a rectangularshape) and then annealed. In assembling a core with a preformedconductive transformer winding, preferably one or more packets of stripsegments are taken out one at a time from the inside of the core, i.e.,P-1 first, P-2 second, etc. Each packet or group of packets is sprungopen to allow it to be passed through the window of the conductivewinding and after it has been passed through the winding it is allowedto spring back to its annealed position. As the packets are assembledone outside another, care is taken to see that the joints are properlyfitted. It is also frequently desirable, particularly in reassemblingthe last or outermost packet of segments around a preformed coil, toremove one or more strip segments from a packet and reassemble themsequentially around the preformed coil. When the assembly is complete, athin steel strap or band may be applied around the core to hold the corein firmly assembled relationship, or the outer segment may be tackwelded at its joint.

To replace the carriage 9 in its initial position (FIG. 2) for the nextcore loop building operation, the air cylinder AC is actuated to pullthe roll 259 and consequently carriage 5 to the left as viewed in FIG. 3to their FIG. 2 positions.

The switch 447 is set to produce the desired number of strip segmentsper packet as described above (assuming it is desired to change thenumber of segments per packet of the next core loop) and the clutch 43is actuated to start the various driving belts, gears and chains inoperation, thus initiating the building of another core loop.

If it is desired to make a core loop in which the joints of one packetare offset from the joints of the segments of the preceding packet by adesired amount, say, 180 for example, it will be understood that suchoffsetting may be simply accomplished. For example, a dog clutch may beprovided in the drive between the shaft 21 and the tubular shaft 351(FIGS. 13 and 14), which dog clutch could be actuated to rotate theshaft 21 (and consequently brushes BS, BT and BE) 180 after any onepacket or each packet of strip segments had been wound. This wouldresult in a core loop having the joints of the segments of any onepacket or each packet offset from the joints of the segments of thepreceding and succeeding packets by 180. Another example foraccomplishing the same results would be to provide a second set ofbrushes BS, BT and BE on a second brush plate located the desiredamount, 180 for example, out of phase with the first set of brushes BS,BT and BE and brush carrying plate 341. The second set of brushes wouldbe alternately connected in the control circuit at the time or times itwould be desired to wind a packet having the segment joints thereofoffset from the segment joints of other packets. Still another exampleof accomplishing the same result would be to provide a second set ofconductive segments on the commutator plate the desired amount, forexample, from the corresponding conductive segments 339-1 to 339-20. Thesecond set of conductive segments would be alternately connected in thecontrol circuit (and the segments 339-1 to 339-20 would be disconnected)when it is desired to wind a packet having the segment joints thereofoffset from the segment joints of other packets. Thus, the joints in allof the packets of a core formed in accordance with this invention mayconveniently be caused to fall in any particular desired area, such asone of the legs of a rectangular core or alternate legs, or in one yokeportion, etc.

While the shear 7 is shown as being operated by a double rack mechanism,it will be understood that other shear operating mechanisms may beutilized with equal effectiveness. Ror example, a solenoid operatedshear having a blade adapted to move upwardly from the lower side of thestrip S to cut a segment therefrom could be used. Moreover, while theapparatus disclosed herein is shown as being adapted for fabricating orbuilding =core loops having concentric segments with offset abuttingjoints, it will be apparent to those skilled in this art that bychanging various feaures of the apparatus, such as the shape and size ofthe conductive segments 339-1 to 339-20, other types of core loops, suchas core loops in which the segments thereof have lapped and/ or radiallyaligned joints could be made.

While the core form 1 is shown herein as being circular, it will beunderstood that core forms other than circular, such as rectangular forexample, could be utilized without departing from the spirit of theinvention. If a rectangular core form were used, for example, thearrangement of parts (wrapping belt 3, bands 11, etc.) for moving thecarriage 9 to the right as viewed in FIGS. 1, 2 and 3 would stillfunction to move the carriage between each shearing operation in suchdirection by an amount equal to the increase in the perimeter of thecore loop being wound. It will also be noted that instead of using asingle thickness of strip S for forming strip segments of progressivelyincreasing length, two or more strips, one on top of the other, may befed into the apparatus and each strip segment will be two or moresuperposed plies of gram-oriented ribbon, each of identical length.

In View of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above methods without departingfrom the scope of the invention, it is intended that all mattercontained in the above descript1on or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. The method of forming a core loop comprising feeding a continuousstrip of magnetic material toward a rotating core form, intermittentlycutting the strip to form individual strip segments, sequentially movingthe leading ends of the strip segments toward the core form atpredetermined intervals, wrapping each of the segrnents thus formed onthe rotating core form, sensing the increase in the perimeter of thecore loop as the segments are wrapped around the core form, andprogressively shifting the locus of the cut relative to the core form bya distance proportional to the sensed increase in perimeter toprogressively increase the length of the segments cut from the strip.

2. The method of forming a core loop comprising feeding a continuousstrip of magnetic material toward a rotating core form, intermittentlyarresting the feed of the strip with the leading end of the strippositioned adjacent the rotating core form, intermittently cutting thestrip to form individual strip segments when said strip is

4. THE METHOD OF FORMING A CORE LOOP COMPRISING FEEDING A CONTINUOUSSTRIP OF MAGNETIC MATERIAL TOWARD A ROTATING CORE FORM, INTERMITTENTLYARRESTING THE FEED OF THE STRIP WITH THE LEADING END OF THE STRIPPOSITIONED ADJACENT THE CORE FORM, CUTTING THE STRIP DURING THE DWELLINTERVALS OF THE STRIP BETWEEN SUCCESSIVE FEEDING OPERATIONS,PROGRESSIVELY SHIFTING THE LOCUS OF THE CUT IN THE DIRECTION AWAY FROMTHE CORE FORM IN RESPONSE TO THE